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Abstract Background Stem cell factor (SCF) receptor c-Kit is recognized as a key signaling molecule, which transduces signals for the proliferation, differentiation and survival of stem cells. Binding of SCF to its receptor triggers transactivation, leading to the recruitment of kinases and phosphatases to the docking platforms of c-Kit catalytic domain. Tyrosine phosphatase-1 (Shp-1) deactivates/attenuates 'Kit' kinase activity. Whereas, Asp816Val mutation in the Kit activation loop transforms kinase domain to a constitutively activated state (switch off-to-on state), in a ligand-independent manner. This phenomenon completely abrogates negative regulation of Shp-1. To predict the possible molecular basis of interaction between c-Kit and Shp-1, we have performed an in silico protein-protein docking study between crystal structure of activated c-Kit (phosphorylated c-Kit) and full length crystal structure of Shp-2, a close structural counterpart of Shp-1. Findings Study revealed a stretch of conserved amino acids (Lys818 to Ser821) in the Kit activation domain, which makes decisive H-bonds with N-sh2 and phosphotyrosine binding pocket residues of the phosphatase. These H-bonds may impose an inhibitory steric hindrance to the catalytic domain of c-Kit, there by blocking further interaction of the activation loop molecules with incoming kinases. We have also predicted a phosphotyrosine binding pocket in SH2 domains of Shp-1, which is found to be predominantly closer to a catalytic groove like structure in c-Kit kinase domain. Conclusions This study predicts that crucial hydrogen bonding between N-sh2 domain of Shp-1 and Kit activation loop can modulate the negative regulation of c-Kit kinase by Shp-1. Thus, this finding is expected to play a significant role in designing suitable gain-of-function c-Kit mutants for inducing conditional proliferation of hematopoietic stem cells.

Background and Objective: Glutathione S-transferases (GSTs) belong to a family of ubiquitous and multifunctional enzymes that work as one of the endogenous antioxidants in our body. This study was designed to look into the association of GST polymorphism with oxidative stress in both diabetic and nondiabetic chronic kidney disease (CKD). Design and Methods: Three groups of patients (50 in each): diabetics without CKD (DM), diabetic CKD (DM-CKD), and nondiabetic CKD (NDM-CKD) and 50 age- and sex-matched healthy controls were recruited. Genotyping was done for GSTM1 and GSTT1 genes using a multiplex polymerase chain reaction. Serum GST and malondialdehyde (MDA) as a marker of oxidative stress were measured spectrophotometrically. Results: Based on genotyping, subjects were categorized as GSTM1+/GSTT1+, GSTM1−/GSTT1+, GSTM1+/GSTT1−, and GSTM1−/GSTT1−. Serum GST levels were lower among subjects with deletion in one/both GST genes, whereas MDA levels were found to be correspondingly raised. A negative correlation for MDA versus GST levels was observed among genotypes with one/both gene deletions. Presence of GSTM1+/GSTT1− and GSTM1−/GSTT1− was significantly higher among patients with CKD in both diabetics and nondiabetics. Interpretations and Conclusions: GSTM1 and GSTT1 deletions singly or together were associated with lower GST levels and higher oxidative stress in both diabetic and nondiabetic CKD. Interestingly, GSTT1 deletion appears to be associated with both diabetic and nondiabetic CKD irrespective of the GSTM1 status. [ABSTRACT FROM AUTHOR]

Hyperlipidemia and increased serum lipoprotein (Lp)(a) are independent risk factors for atherosclerosis and its complications. Serum Lp(a) concentration is not influenced by most lipid-lowering therapies other than niacin. Recently aspirin also has been reported to decrease its levels. In the current study, we evaluated the serum levels of Lp(a) and lipids in 25 patients with first-ever diagnosed ischemic stroke, aged 21 to 60 years, and compared their levels with an equal number of age- and sex-matched healthy control subjects. In addition, the effect of aspirin on Lp(a) levels was studied by estimating its levels after 4 weeks of daily treatment with 150 mg of aspirin. Both groups were comparable regarding their anthropometric measurements and routine laboratory parameters except that erythrocyte sedimentation rate was higher in the patients. Serum lipids were not significantly different between the two groups, although Lp(a) levels were significantly higher in the patients (27.40 ± 22.30 mg/dL) as compared with the control subjects (14.68 ± 11.75 mg/dL) (P = .005). Twenty of 25 patients (80%) had serum Lp(a) levels of more than 10 mg/dL, whereas only 11 of 25 control subjects (44%) had serum Lp(a) levels of more than 10 mg/dL (P = .009). After 4 weeks of treatment with aspirin, Lp(a) levels declined significantly (46.24%) from baseline 27.40 ± 22.30 mg/dL to 14.73 ± 10.47 mg/dL (P < .001). Patients with baseline levels greater than 25 mg/dL showed greater decline (55.63%) compared with those with levels less than 25 mg/dL (26.63%) (P = .008). Results of our study confirm that aspirin lowers the increased Lp(a) levels in patients with ischemic stroke. [Copyright &y& Elsevier]

Aim: To investigate the association of NFKB1 gene -94 ATTG insertion/deletion (rs28362491) polymorphism with inflammatory markers and risk of diabetic nephropathy in Asian Indians., Methods: A total of 300 subjects were recruited (100 each), normoglycemic, (NG); type 2 diabetes mellitus (T2DM) without any complications (DM) and T2DM with diabetic nephropathy [DM-chronic renal disease (CRD)]. Analysis was carried out by polymerase chain reaction-restriction fragment length polymorphism and ELISA. Pearson's correlation, analysis of variance and logistic regression were used for statistical analysis., Results: The allelic frequencies of -94 ATTG insertion/deletion were 0.655/0.345 (NG), 0.62/0.38 (DM) and 0.775/0.225 (DM-CRD). The -94 ATTG ins allele was associated with significantly increased levels of urinary monocyte chemoattractant protein-1 (uMCP-1); uMCP-1 ( P = 0.026) and plasma tumor necrosis factor-alpha (TNF-α); TNF-α ( P = 0.030) and almost doubled the risk of diabetic nephropathy (OR = 1.91, 95%CI: 1.080-3.386, P = 0.025)., Conclusion: -94 ATTG ins/ins polymorphism might be associated with increased risk of developing nephropathy in Asian Indian subjects with diabetes mellitus., Competing Interests: Conflict-of-interest statement: No conflict of interest exists for this study.

Inherited deficiency of certain factors is responsible for increased tendency to vascular thrombosis; however two genetic defects in the coagulation pathway may coexist and cause recurrent thrombosis. Previously studies of thrombophilia have focused on the identification of single gene defects with the concept that familial thrombophilia is a single gene disorder. Now it has become accepted that familial thrombosis in protein C-deficient families is caused by co-segregation of one or more additional genetic factors that increase the risk of thrombosis. Co-existence of two or more genetic abnormalities increases the risk of thrombotic tendencies in affected persons. Simultaneous presence of factor V Leiden and deficiency of protein C results in higher risk of thrombosis. We report two such cases with additional analysis of the family tree highlighting that dual abnormality results in higher penetrance of the disease among family members.